【作者】 游金兰；

【导师】 周绪红；

【作者基本信息】 长安大学 ， 桥梁与隧道工程， 2008， 硕士

【摘要】 预应力混凝土曲线梁桥受到平面曲率的影响,在荷载作用下发生竖向弯曲的同时,必然会产生扭转,而这种扭转作用又会导致梁的挠曲变形,本文针对曲线箱梁桥这种“弯扭耦合”受力特性,对曲线梁在弯曲与非对称扭转共同作用下的扭转相关性能进行了研究。推导了空间预应力等代荷载的计算公式,给出了混凝土曲线箱梁由预应力引起的扭矩的计算公式,并应用有限元程序对预应力引起的效应从箱梁横截面应力层面上进行分析。推导了预应力混凝土曲线箱梁在弯曲和非对称扭转共同作用下的翘曲应力和翘曲双力矩的计算公式,并应用初参数法进行求解。结合工程实际,研究了单位移动正载及偏载作用下,不同位置箱梁截面的翘曲双力矩及扭矩的变化规律。引入翘曲比对截面翘曲程度进行描述。基于变角度空间桁架模型,考虑混凝土软化效应,对预应力混凝土曲线箱梁的抗扭承载力计算公式进行推导。利用有限元方法对两跨连续预应力混凝土曲线箱梁桥进行了分析,给出了曲线箱梁在自重、预应力及外荷载作用下截面应力及位移的分布,并根据计算结果给出了复合荷载作用下,曲线箱梁内外侧腹板主应力的等值线图。提出了预应力混凝土曲线箱梁桥的设计方法,并进行了该类桥型的实例设计。更多还原

【Abstract】 Due to the influence of plan curvature, under load the torsion will appear inevitably in curved girder bridge, which will also cause bending deformation. Aimed at the flexure-torsion coupling mechanical property of curved prestressed concrete girder bridge, under bending and asymmetrical torsional load, the properties correlation with torsion were researched in this article.The formula of equipollent load of spatial pre-stress was deduced based on the equilibrium equation of curved prestressed concrete girder bridge. The formula of twist moment caused by spatial pre-stress was also deduced. Stress distribution of the boxing section caused by pre-stress was analyzed by spatial finite element method.Under bending and asymmetrical torsional load, the formulas, which were fit to analyze the warp stress and warp bimoment of curved prestressed concrete girder, were established. The equations of warp bimoment could be solved by the initial parameter method. Based on case study, under unit positive and eccentric loads the variable rules of warp bimoment and torsion of the boxing section were studied. Warp ratio was presented to describe the distortion degree of boxing section.On the basis of variable-angle spatial truss model theory, considering softening of concrete, the equation which was appropriate for calculating the ultimate torsional strength of curved prestressed concrete girder was deduced.A two spans continuous curved prestressed concrete girder bridge was analyzed by the spatial finite element method. The stress and deflection distributions under different loads were showed in the article. According to the calculated result, primary stress contour charts of inward and outward web which was under composite load were given out.The design method of curved prestressed concrete box girder was proposed. And a relevant design example was presented.更多还原